Every year, thousands of tons of commodities are transported along the nation's inland waterways via a combination of towboats and barges, referred to collectively as a “tow.” There are four main types of barges, including: open, closed, sealed and liquid. Each type has three different sizes: a standard barge is 26′×175′; a jumbo barge is 35′×195′ and a “stumbo” barge is 26′×195′. Typically, a single tow can have up to 15 barges. The average barge can carry a approximately 1,500 tons of a given commodity, a payload equal to about 60 typical tractor/trailer style trucks commonly seen on America's highways. This large payload capacity makes transferring commodities by barge more efficient than any other means of commercial transportation.
The inland waterway system in the U.S. contains many locks and dams, typically built by the Army Corps of Engineers, to prevent flooding in low-lying riverside areas and to provide for stable navigation. To traverse the dams, it is necessary that the tows negotiate passage through many locks. As an example, to transport a commodity from Pittsburgh to St. Louis along the Ohio River, it is necessary for a tow to pass through over twenty locks. The dimensions of many old locks are such that every time a tow has to traverse a lock, it may have to perform double or even triple lockage, depending on river conditions and tow size. This can cause bottlenecks along the river. A single accident at a lock can cause exponential river jams. In addition to varying lock configuration, weather conditions, such as fog, darkness, harsh river conditions, and other variables provide a significant amount of unpredictability.
The locking process has a history of nearly a century without much innovation. Almost every lock approach is unique because of variables such as lock dimensions and configuration, current speed, visibility, water levels, tow configurations, etc. All of these variables play a part in determining a safe and speedy lockage. Traversing locks requires a high degree of precision and piloting skill; the usual allowable clearance between the lock wall and the tow may be as little as 2.5 feet on each side of the tow. This makes it very difficult for pilots who are unfamiliar with a lock to navigate it successfully in an efficient manner.
Traditionally, the locking process is a slow and manual operation with complete reliance on the judgment of the tow pilot and communication of the tow's position by deckhands via handheld radios. Locks present a serious threat to the safety and efficiency of the inland waterways because of expensive accidents, decreased throughput and delay costs that can lead to unreliable delivery schedules and, on occasion, cargo loss resulting from collisions with locks. Thus, there is a need for a system to address many of the issues that often delay freight while being transported on the river system.
By improving a captain's ability to navigate locks in fog, reducing lock transit times, and decreasing the number of debilitating accidents, the waterborne shipping industry could realize tremendous annual savings. Further, increased predictability and decreased transit times would allow more cargo to use the environmentally friendly in-land waterways, thereby reducing traffic on strained road and rail systems and increasing the economic importance of areas in which waterways reside.
Accordingly, it would be desirable to provide an electronic system that will improve the safety and efficiency of the inland waterway system by reducing shipping bottlenecks and improving predictability. First, such a system would preferably reduce average delay and lockage times by providing a way of navigating locks in adverse weather, and in particular, in foggy conditions. Second, it is desired that the dependence of the tow pilot on deckhands for information regarding tow position with respect to the locks be reduced.